Barbara J. Comly - Aug 13, 2025 Form 3 Insider Report for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX)

Signature
/s/Alessandra Maria Corona Henriques, Attorney-in-Fact
Stock symbol
MIAX
Transactions as of
Aug 13, 2025
Transactions value $
$0
Form type
3
Date filed
8/13/2025, 05:09 PM
Next filing
Aug 19, 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Comly Barbara J. EVP, GC & Corporate Secretary C/O MIAMI INTERNATIONAL HOLDINGS, INC., 7 ROSZEL ROAD, SUITE 1A, PRINCETON /s/Alessandra Maria Corona Henriques, Attorney-in-Fact 2025-08-13 0002080878

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
holding MIAX Common Stock 869K Aug 13, 2025 Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
holding MIAX Series B Preferred Stock Aug 13, 2025 Common Stock 101K Direct F1
holding MIAX Nonvoting Common Stock Aug 13, 2025 Common Stock 156K Direct F2
holding MIAX Incentive Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 8.33K $12.00 Direct F3
holding MIAX Incentive Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 16.7K $12.00 Direct F3
holding MIAX Incentive Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 8.33K $12.00 Direct F3
holding MIAX Incentive Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 13.1K $15.22 Direct F3
holding MIAX Incentive Stock Option (Right to Buy) Aug 13, 2025 Common Stock 10.1K $19.84 Direct F4
holding MIAX Incentive Stock Option (Right to Buy) Aug 13, 2025 Common Stock 4.98K $20.08 Direct F5
holding MIAX Incentive Stock Option (Right to Buy) Aug 13, 2025 Common Stock 4.46K $22.40 Direct F6
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 142K $12.00 Direct F7
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 133K $12.00 Direct F7
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 142K $12.00 Direct F7
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 137K $15.22 Direct F7
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Nonvoting Common Stock 150K $16.14 Direct F7
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Common Stock 115K $19.84 Direct F8
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Common Stock 95K $20.08 Direct F9
holding MIAX Nonqualified Stock Option (Right to Buy) Aug 13, 2025 Common Stock 70.5K $22.40 Direct F10
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 The shares of Series B Preferred Stock are convertible on a one-for-one basis into shares of common stock commencing on the Company's initial public offering of its common stock ("IPO") effective date, which is August 13, 2025. The Series B Preferred Stock has no expiration date.
F2 The shares of nonvoting common stock are convertible on a one-for-one basis into shares of common stock commencing at any time. The nonvoting common stock has no expiration date.
F3 The incentive stock options are fully vested. The options were granted initially as the right to buy nonvoting common stock. On the closing date of the IPO, these will convert to the right to buy common stock instead of nonvoting common stock.
F4 5,040 of the shares subject to this incentive stock option are vested and the remaining 5,040 will vest on March 29, 2026 subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F5 All of the shares subject to this incentive stock option will vest on June 10, 2027, subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F6 All of the shares subject to this incentive stock option will vest on June 16, 2028, subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F7 The nonqualified stock options are fully vested. The options were granted initially as the right to buy nonvoting common stock. On the closing date of the IPO, these will convert to the right to buy common stock instead of nonvoting common stock.
F8 78,294 of the shares subject to this nonqualified stock option are vested and the remaining 36,626 will vest on March 29, 2026 subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F9 33,334 of the shares subject to this nonqualified stock option are vested, 33,333 will vest on June 10, 2026 and the remaining 28,353 will vest on June 10, 2027, subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F10 25,000 of the shares subject to this nonqualified stock option will vest on June 16, 2026, 25,000 will vest on June 16, 2027 and the remaining 20,536 will vest on June 16, 2028, subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.

Remarks:

See Exhibit 24.1 - Power of Attorney